Most vehicles with automatic stepped variable speed transmissions, change-under-load automatic transmissions or automated shift transmissions are equipped with a so-termed kick-down switch. As a rule the actuation of the kick-down switch is interpreted to mean that the maximum traction force is demanded. Starting from a driving condition in which the kick-down switch is actuated, if a downshift is permitted because of the engine speeds anticipated, this is carried out.
To actuate the kick-down switch, as a rule the driver has to overcome some more resistance even when the accelerator pedal is almost fully depressed, so that the driver obtains feedback via this actuation force that further depression of the accelerator pedal is needed to trigger the kick-down program.
Compared with vehicles without a kick-down switch, the respective driving condition can be differentiated essentially more reliably and downshifts can be deliberately triggered or suppressed by the driver, only by corresponding actuation of the accelerator pedal.
In the case of heavy goods vehicles, particularly in the range of the maximum permitted speed on roads, namely 60 km/h, it is virtually impossible to design a gear shift program “optimally”. The requirements for minimal fuel consumption and for sufficient excess traction to enable accelerations and/or driving up slight upward slopes are irreconcilably opposed, if at the same time too frequent gear shifting or cycling between gears is to be avoided. In other words, if the shifting program is designed for minimum fuel consumption, then an upshift to the next gear step up or to the top gear already takes place early. Then, as a result of the lower engine speed, in that gear step there is only little excess traction force, so that even when a small acceleration is called for, a downshift is again needed.
In practice, therefore, an actuator element is often provided which allows the driver to take action manually, so that he can suppress a gear shift or bring it about deliberately. This has the disadvantage that the fully automatic operating mode does not satisfactorily cover every driving situation.
Accordingly, the purpose of the present invention is to indicate a method for controlling an automatic gearshift stepped variable speed transmission, which allows a driver, especially in driving situations on an essentially level road, to influence the engaged gear deliberately without having to abandon the automatic operating mode.